Kconfig 9.9 KB

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  1. #
  2. # General architecture dependent options
  3. #
  4. config OPROFILE
  5. tristate "OProfile system profiling"
  6. depends on PROFILING
  7. depends on HAVE_OPROFILE
  8. select RING_BUFFER
  9. select RING_BUFFER_ALLOW_SWAP
  10. help
  11. OProfile is a profiling system capable of profiling the
  12. whole system, include the kernel, kernel modules, libraries,
  13. and applications.
  14. If unsure, say N.
  15. config OPROFILE_EVENT_MULTIPLEX
  16. bool "OProfile multiplexing support (EXPERIMENTAL)"
  17. default n
  18. depends on OPROFILE && X86
  19. help
  20. The number of hardware counters is limited. The multiplexing
  21. feature enables OProfile to gather more events than counters
  22. are provided by the hardware. This is realized by switching
  23. between events at an user specified time interval.
  24. If unsure, say N.
  25. config HAVE_OPROFILE
  26. bool
  27. config OPROFILE_NMI_TIMER
  28. def_bool y
  29. depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
  30. config KPROBES
  31. bool "Kprobes"
  32. depends on MODULES
  33. depends on HAVE_KPROBES
  34. select KALLSYMS
  35. help
  36. Kprobes allows you to trap at almost any kernel address and
  37. execute a callback function. register_kprobe() establishes
  38. a probepoint and specifies the callback. Kprobes is useful
  39. for kernel debugging, non-intrusive instrumentation and testing.
  40. If in doubt, say "N".
  41. config JUMP_LABEL
  42. bool "Optimize very unlikely/likely branches"
  43. depends on HAVE_ARCH_JUMP_LABEL
  44. help
  45. This option enables a transparent branch optimization that
  46. makes certain almost-always-true or almost-always-false branch
  47. conditions even cheaper to execute within the kernel.
  48. Certain performance-sensitive kernel code, such as trace points,
  49. scheduler functionality, networking code and KVM have such
  50. branches and include support for this optimization technique.
  51. If it is detected that the compiler has support for "asm goto",
  52. the kernel will compile such branches with just a nop
  53. instruction. When the condition flag is toggled to true, the
  54. nop will be converted to a jump instruction to execute the
  55. conditional block of instructions.
  56. This technique lowers overhead and stress on the branch prediction
  57. of the processor and generally makes the kernel faster. The update
  58. of the condition is slower, but those are always very rare.
  59. ( On 32-bit x86, the necessary options added to the compiler
  60. flags may increase the size of the kernel slightly. )
  61. config OPTPROBES
  62. def_bool y
  63. depends on KPROBES && HAVE_OPTPROBES
  64. depends on !PREEMPT
  65. config HAVE_EFFICIENT_UNALIGNED_ACCESS
  66. bool
  67. help
  68. Some architectures are unable to perform unaligned accesses
  69. without the use of get_unaligned/put_unaligned. Others are
  70. unable to perform such accesses efficiently (e.g. trap on
  71. unaligned access and require fixing it up in the exception
  72. handler.)
  73. This symbol should be selected by an architecture if it can
  74. perform unaligned accesses efficiently to allow different
  75. code paths to be selected for these cases. Some network
  76. drivers, for example, could opt to not fix up alignment
  77. problems with received packets if doing so would not help
  78. much.
  79. See Documentation/unaligned-memory-access.txt for more
  80. information on the topic of unaligned memory accesses.
  81. config ARCH_USE_BUILTIN_BSWAP
  82. bool
  83. help
  84. Modern versions of GCC (since 4.4) have builtin functions
  85. for handling byte-swapping. Using these, instead of the old
  86. inline assembler that the architecture code provides in the
  87. __arch_bswapXX() macros, allows the compiler to see what's
  88. happening and offers more opportunity for optimisation. In
  89. particular, the compiler will be able to combine the byteswap
  90. with a nearby load or store and use load-and-swap or
  91. store-and-swap instructions if the architecture has them. It
  92. should almost *never* result in code which is worse than the
  93. hand-coded assembler in <asm/swab.h>. But just in case it
  94. does, the use of the builtins is optional.
  95. Any architecture with load-and-swap or store-and-swap
  96. instructions should set this. And it shouldn't hurt to set it
  97. on architectures that don't have such instructions.
  98. config HAVE_SYSCALL_WRAPPERS
  99. bool
  100. config KRETPROBES
  101. def_bool y
  102. depends on KPROBES && HAVE_KRETPROBES
  103. config USER_RETURN_NOTIFIER
  104. bool
  105. depends on HAVE_USER_RETURN_NOTIFIER
  106. help
  107. Provide a kernel-internal notification when a cpu is about to
  108. switch to user mode.
  109. config HAVE_IOREMAP_PROT
  110. bool
  111. config HAVE_KPROBES
  112. bool
  113. config HAVE_KRETPROBES
  114. bool
  115. config HAVE_OPTPROBES
  116. bool
  117. config HAVE_NMI_WATCHDOG
  118. bool
  119. #
  120. # An arch should select this if it provides all these things:
  121. #
  122. # task_pt_regs() in asm/processor.h or asm/ptrace.h
  123. # arch_has_single_step() if there is hardware single-step support
  124. # arch_has_block_step() if there is hardware block-step support
  125. # asm/syscall.h supplying asm-generic/syscall.h interface
  126. # linux/regset.h user_regset interfaces
  127. # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
  128. # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
  129. # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
  130. # signal delivery calls tracehook_signal_handler()
  131. #
  132. config HAVE_ARCH_TRACEHOOK
  133. bool
  134. config HAVE_DMA_ATTRS
  135. bool
  136. config HAVE_DMA_CONTIGUOUS
  137. bool
  138. config USE_GENERIC_SMP_HELPERS
  139. bool
  140. config GENERIC_SMP_IDLE_THREAD
  141. bool
  142. config HAVE_REGS_AND_STACK_ACCESS_API
  143. bool
  144. help
  145. This symbol should be selected by an architecure if it supports
  146. the API needed to access registers and stack entries from pt_regs,
  147. declared in asm/ptrace.h
  148. For example the kprobes-based event tracer needs this API.
  149. config HAVE_CLK
  150. bool
  151. help
  152. The <linux/clk.h> calls support software clock gating and
  153. thus are a key power management tool on many systems.
  154. config HAVE_DMA_API_DEBUG
  155. bool
  156. config HAVE_HW_BREAKPOINT
  157. bool
  158. depends on PERF_EVENTS
  159. config HAVE_MIXED_BREAKPOINTS_REGS
  160. bool
  161. depends on HAVE_HW_BREAKPOINT
  162. help
  163. Depending on the arch implementation of hardware breakpoints,
  164. some of them have separate registers for data and instruction
  165. breakpoints addresses, others have mixed registers to store
  166. them but define the access type in a control register.
  167. Select this option if your arch implements breakpoints under the
  168. latter fashion.
  169. config HAVE_USER_RETURN_NOTIFIER
  170. bool
  171. config HAVE_PERF_EVENTS_NMI
  172. bool
  173. help
  174. System hardware can generate an NMI using the perf event
  175. subsystem. Also has support for calculating CPU cycle events
  176. to determine how many clock cycles in a given period.
  177. config HAVE_ARCH_JUMP_LABEL
  178. bool
  179. config HAVE_ARCH_MUTEX_CPU_RELAX
  180. bool
  181. config HAVE_RCU_TABLE_FREE
  182. bool
  183. config ARCH_HAVE_NMI_SAFE_CMPXCHG
  184. bool
  185. config HAVE_ALIGNED_STRUCT_PAGE
  186. bool
  187. help
  188. This makes sure that struct pages are double word aligned and that
  189. e.g. the SLUB allocator can perform double word atomic operations
  190. on a struct page for better performance. However selecting this
  191. might increase the size of a struct page by a word.
  192. config HAVE_CMPXCHG_LOCAL
  193. bool
  194. config HAVE_CMPXCHG_DOUBLE
  195. bool
  196. config ARCH_WANT_OLD_COMPAT_IPC
  197. bool
  198. config HAVE_ARCH_MMAP_RND_BITS
  199. bool
  200. help
  201. An arch should select this symbol if it supports setting a variable
  202. number of bits for use in establishing the base address for mmap
  203. allocations, has MMU enabled and provides values for both:
  204. - ARCH_MMAP_RND_BITS_MIN
  205. - ARCH_MMAP_RND_BITS_MAX
  206. config ARCH_MMAP_RND_BITS_MIN
  207. int
  208. config ARCH_MMAP_RND_BITS_MAX
  209. int
  210. config ARCH_MMAP_RND_BITS_DEFAULT
  211. int
  212. config ARCH_MMAP_RND_BITS
  213. int "Number of bits to use for ASLR of mmap base address" if EXPERT
  214. range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
  215. default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
  216. default ARCH_MMAP_RND_BITS_MIN
  217. depends on HAVE_ARCH_MMAP_RND_BITS
  218. help
  219. This value can be used to select the number of bits to use to
  220. determine the random offset to the base address of vma regions
  221. resulting from mmap allocations. This value will be bounded
  222. by the architecture's minimum and maximum supported values.
  223. This value can be changed after boot using the
  224. /proc/sys/vm/mmap_rnd_bits tunable
  225. config HAVE_ARCH_MMAP_RND_COMPAT_BITS
  226. bool
  227. help
  228. An arch should select this symbol if it supports running applications
  229. in compatibility mode, supports setting a variable number of bits for
  230. use in establishing the base address for mmap allocations, has MMU
  231. enabled and provides values for both:
  232. - ARCH_MMAP_RND_COMPAT_BITS_MIN
  233. - ARCH_MMAP_RND_COMPAT_BITS_MAX
  234. config ARCH_MMAP_RND_COMPAT_BITS_MIN
  235. int
  236. config ARCH_MMAP_RND_COMPAT_BITS_MAX
  237. int
  238. config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
  239. int
  240. config ARCH_MMAP_RND_COMPAT_BITS
  241. int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
  242. range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
  243. default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
  244. default ARCH_MMAP_RND_COMPAT_BITS_MIN
  245. depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
  246. help
  247. This value can be used to select the number of bits to use to
  248. determine the random offset to the base address of vma regions
  249. resulting from mmap allocations for compatible applications This
  250. value will be bounded by the architecture's minimum and maximum
  251. supported values.
  252. This value can be changed after boot using the
  253. /proc/sys/vm/mmap_rnd_compat_bits tunable
  254. config HAVE_ARCH_SECCOMP_FILTER
  255. bool
  256. help
  257. An arch should select this symbol if it provides all of these things:
  258. - syscall_get_arch()
  259. - syscall_get_arguments()
  260. - syscall_rollback()
  261. - syscall_set_return_value()
  262. - SIGSYS siginfo_t support
  263. - secure_computing is called from a ptrace_event()-safe context
  264. - secure_computing return value is checked and a return value of -1
  265. results in the system call being skipped immediately.
  266. - seccomp syscall wired up
  267. config SECCOMP_FILTER
  268. def_bool y
  269. depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
  270. help
  271. Enable tasks to build secure computing environments defined
  272. in terms of Berkeley Packet Filter programs which implement
  273. task-defined system call filtering polices.
  274. See Documentation/prctl/seccomp_filter.txt for details.
  275. source "kernel/gcov/Kconfig"